It has long been recognized that the heating of materials within an oven enclosure will be more uniform and rapid if a forced ventilation system is employed rather than relying on air currents induced by temperature differences. More recently this concept has been employed in cooking ovens.
Early recognition of this concept is found in U.S. Pat. No. 2,412,103 to Spooner and U.S. Pat. No. 2,957,067 to Scofield.
The importance of uniform heat to cooking and to baking in particular is known to anyone who has seen cookies burn on one shelf in an oven but not on another, or seen the items in the middle of a pan burn, or observed other effects indicating uneven heating at various locations within an oven. With the onset of energy problems and rising leisure expectations in the modern era, shorter cooking time and lesser energy consumption became more important factors.
Recently others have invented structures designed for cooking or baking ovens and stove ovens. Examples are U.S. Pat. Nos. 3,168,642 to Savio and 3,812,837 to Tadayoshi disclosing structures to increase the rate and uniformity of cooking and baking within the oven.
In an oven without an air handling device to force an air current, air circulates by means of temperature differences in the oven with currents of warmed air rising and cooler air sinking. These currents may not be uniform within the oven, and may change as pans and trays are added. These currents cannot exist without parts of the oven being hotter than others. Also, air is a fairly poor heat conductor and thermal currents move it only slowly so that heat transfer to the cooking food is a slow process.
While the aforementioned patents do disclose ovens with forced air circulation mechanisms for producing air currents within an oven, they are built into the oven itself thus allowing the driving motor to be disposed outside of the oven interior. These structures are accordingly expensive and are not adapted for use with ovens not so equipped by the original manufacturer.
It is accordingly desirable that an oven air circulator be provided in the way of a portable accessory that can be used only when necessary or desirable and which may be located where there is room within an oven and so as to produce optimal circulation in the cooking oven.